1. Field
Example embodiments of the inventive concepts relate to a semiconductor device, and more particularly, to a semiconductor device including a gate structure and a method of manufacturing the semiconductor device.
2. Description of the Related Art
A metal oxide semiconductor (MOS) transistor using polysilicon is widely known as an example of a gate electrode. Polysilicon is more durable than most metals at a relatively high temperature so that polysilicon along with source and drain regions may be annealed at the relatively high temperature. Polysilicon may be used to form a self-aligned source and drain structure after gate patterning is complete. However, because polysilicon has relatively high resistance compared to most metal materials, a polysilicon gate electrode has a lower operating speed than a metal gate electrode. As a method of compensating for the relatively high resistance of polysilicon, a method of replacing the polysilicon gate electrode with the metal gate electrode may be used. Such a method may be performed using a replacement metal gate (RMG) process. While polysilicon exists on a semiconductor substrate, a relatively high temperature process may be performed, and then, a metal gate may be formed by removing the polysilicon and replacing it with metal.